Factors predicting lymph node metastasis in clinical stage T1aN0M0 lung adenocarcinomas

Abstract

Objective To determine the risk factors of lymph node metastasis in clinical stage T1aN0M0 lung adenocarcinomas. Methods Among a consecutive of 5312 patients with non-small lung cancer undergoing surgical resection at Shanghai Chest Hospital between January 2011 and December 2012, the clinical records of 273 patients with clinical stage T1aN0M0 lung adenocarcinomas were retrospectively analysed. Preoperative CT categorized the tumors of 273 patients as pure ground glass opacity(GGO), GGO with minimal solid components (diameter of solid part<5mm), part-solid (diameter of solid parts≥5mm) and pure solid. Relevant clinicopathologic features were investigated to identify the risk factors of lymph node metastasis using univariate and multivariate analysis. Results Thin-section CT was performed among all the 273 patients, among whom 103 (37.7%) were pure GGO, 118 (43.2%) GGO with minimal solid components(diameter of solid part<5 mm), 13 (4.8%) part-solid (diameter of solid parts≥5mm), and the other 39 (14.3%) pure solid. There were 18 (6.6%) patients with lymph node metastasis. The incidences of N1 and N2 nodal involvement were 6.5% (11 patients) and 4.1% (7 patients), respectively. No lymph node metastasis occurred in patients with pure GGO and GGO with minimal solid components (diameter of solid part<5mm). Multivariate analysis indicated that symptoms at presentation, diameter of solid parts≥5mm and increased carcinoembryonic antigen (CEA) titer were risk factors of lymph node metastasis of T1a lung adenocarcinomas. Multivariate analysis also revealed that air bronchogram sign, tumor size, symptoms at presentation and increased abnormal CEA titer were risk factors of lymph node metastasis of pure solid tumors (95%CI: 2.001-5.990, P=0.035; 95%CI: 1.000-3.980, P=0.021; 95%CI: 1.887-2.663, P=0.020; 95%CI: 1.514-8.498, P=0.013). Conclusions Lymph node dissection should not be performed among patients of clinical stage T1aN0M0 lung adenocarcinomas with GGO with minimal solid components (diameter of solid part 5ng/ml or symptoms at presentation. Key words: Lymph node; Lung adenocarcinomas; Carcinoma, non-small cell lung; Clinical stage